Hi Arlo - AudioShare is a simple host app that can take a source audio and pass it through effects before it sending it out to headphones etc. It is pretty basic and has what appears to be a small footprint which is good. It would be an ideal host I think. Also the same company produces effects apps that work with AudioShare.
Okay, and the developer just confirmed to me that the EQ app is only a node, so a host app is indeed required.
In any case, just for completeness with regards to SLM - If I compare hosting SLM in AudioShare to other apps (such as SampleTank) you should be able to set them up without having to play the audio first: there is no problem loading SampleTank even when SampleTank is not loaded. I have also tested SLM Garageband (iOS version) and I get the same issue: difficulty in hosting SLM and once done, cannot get the audio to play through the host app. Might be the fact that I am using an old iPad mini (even though it is running the latest IOS).
If I force-quit Set List Maker, then try to select it as an instrument in GarageBand, the Set List Maker sources (4 of them) appear, but when I tap one, I see the message "The Inter-App Audio app you have selected is not available at this time." In contrast, when I select other apps that aren't running, they launch. I don't know why that is. But the solution is simple -- launch Set List Maker and play some audio before trying to select it as a source. After doing that, I don't see any problems. If you see a different problem, please describe it.
Maybe this is crazy but I love the technology as much as I love the music!
I don't think that is unusual. :-)